Final answer:
The Transport Layer of TCP/IP provides communication sessions management and defines the level of service and status of the connection used for data transportation.
Step-by-step explanation:
The TCP/IP layer that provides communication sessions management between host computers, as well as defines the level of service and status of the connection used when transporting data, is the Transport Layer. The Transport Layer is responsible for establishing connections, breaking data into smaller segments, ensuring reliable delivery, and managing flow control. It operates on top of the Internet Protocol (IP) layer.